The automation of dosing processes requires dosing pumps which are particularly suitable for automation and of which hitherto a central position has been occupied by piston or plunger dosers. However, hose squeezing pumps have also been used for dosing purposes, together with displaceable dosing channels with which part of the liquid column can be separated. All these dosing pumps are used in arrangements comprising several of them so as, .e.g., to be able to simultaneously take up and/or supply a plurality of identical volumes. Frequently the pump has to be washed out and filled with another liquid, which requires the use of valves enabling these processes to be controlled and automated.
However, this involves a larger number of simultaneously operating dosing pumps to be used in an arrangement with a minimum amount of space available requiring a large number of parts all acting within a small area. An example is the loading or charging of a microtitre or microtest plate (MTP).
The MTP has been established as an industrial standard in clinical routine diagnosis and in research. It is generally a plastic disposable article with 96 depressions or cavities, which can be used in place of small test tubes for receiving test reagents. The 96 cavities are arranged in a rectangular matrix of 120.times.80 mm and are spaced by only 9 mm from one another. As a function of the geometry of the ,cavities a MTP is suitable for receiving a few microlitres and up to as much as approximately 1 milliter. Thus, the function of automatic dosing is to simultaneously deal with these 96 cavities, which requires 96 dosing pumps with their valves.
For manipulating reagents in connection with microtest plates e.g. multichannel pipettes (8 or 12) or automatic pipetting devices (8 or 12) are known. However, such devices have a capacity limit, which leaves much to be desired. The problem is how is it possible to supply and/or remove liquids with respect to a microtitre plate more rapidly than hitherto and with great accuracy.